Boiler fire tube



v. R. BACHINI BOILER FIRE TUBE Filed May 14@ 1941 Aug. 41

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Inventor www Attorney Patented ug. 4, '1942 UNETED STATES PATENT GFFECE BOILER FIRE TUBE Vasco It. Bachini, Havre, Mont. Application May 14, 1941, Serial No. 393,455

2 Claims. (Cl. 285-25) This invention relates to a tube for a boiler, the general objectof the invention being to provide improved' means for connecting an end of the tube to the tube sheet so that the entire tube end is exposed to the water, thus preventing damage to the tube end from the hot products of combustion.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts to be here- .inafter fully described, illustrated in the accompanying drawing and specifically pointed out in the appended claims.

In describing theinvention in detail, reference will be had to the accompanying drawing wherein like characters denote like or corresponding parts throughout the several views, and in which:

Figure 1 is a longitudinal sectional viewthrough portion of a tube and part of a tube sheet 'showi ing one manner of carrying out the invention.,

Figure -2 is a front view of the tube end and tube sheet as shown in Figure 1.

Figure 3 is a view similar to Figure l and show- 'ing a modification of the invention.

Figure 4 is a similar view showing a further modification of the invention.

As is well known the ordinary way of fastening tubes in tube sheets causes the excessive heat to which the tube end adjacent the rebox is subjected to cause longitudinal and circumferentially extending cracks to occur in the tube which makes the life of the tube short and produces excessive leaks and possible tube collapse that is dangerous to workmen and by-standers.

It is the object of my invention to so form the tube end that the water will contact therewith where the tube end enters the tube sheet so as to prevent these craclns and the tube end is so formed that expansion and contraction can readily take place without damage to either the tube or the-tube sheet.

In that form of the invention shown in Figures 1 and 2 the tube T has that end adjacent the rebox reduced to provide the cylindrical part l and this part is swaged and upset for a suitable length, depending on the size of the boiler which is to receive the tube. This end is much smaller than the hole 2 in the tube sheet S and the swaging and upsetting increases the thickness of the tube wall and thus makes the end of greater strength. The tube end is inserted through the hole 2 and said end is curved outwardly into substantially U-shape with its free end engaging in a countersink 2 of the hole 2 on the rebox side of the sheet and then the parts are -welded to,-

tube is placed in the countersunk hole whichis thenwelded all around as shown at 3 so, as to make a steam-tight and sound joint.

In the modification shown in Figure 3 the free vlimb of the U-shaped part 5 of the tube extends entirely through the hole in the sheet S and the A welding 3' isplaced on both sides of the sheet a shown in Figure 3.

In Figure 4 the U-shaped part 5' is slightly different-fromthat shown in Figure l in that the free limb of the U-shaped part slopes outwardly at an angle away from the part I and, o f course, a die of this shape .must be used..

As. will be seen a space B is formed by the` limbs of the U-shaped part for the.entrance of water so that the water contacts the entire tube end Where it enters the tube sheet so that allA the parts of the tube exposed to the hotrebox gases are protected by the water and this arrangement of the parts also permitting* contraction and expansion of the tube end.

The tube may be manufactured with the reduced end of the U-shaped part or said end may be formedseparately and then welded to the rest of the tube, the'line of welding being shown at 6 in Figure l.

It is thought from the foregoing description that the advantages and novel features of the cent limb, said space forming a water-receiving space which opens out through the water side of the sheet to expose the entire exterior surface 0fthe tube to the water. said short limb tting in the hole in the sheet and means for fastening the short limb in the hole.

2. In a tube connection for a boiler tube sheet having a fire side and a water side and having a hole therein, a tube having one end reduced and the extremity of said end provided with an annular U-shaped part, the short limb being spaced outwardly of the other limb which is formed by the adjacent end part of the reduced part of the tube, said reduced .portion passing through the hole in the sheet with the short limb fitting in the hole and fastened therein, the space formed bythe annular U-shaped part receiving water from the water side of the sheet to expose the entire exterior surface of the tube to the water.

VASCO R. BACIENI. 

